Controller for electric motors



Aixg. 1, 1944. w. E. ADDICKS 2,354,787

CONTROLLER FOR ELECTRIC MOTORS Filed Dec. 7, 1942 6 9 J 7 I8 4 n 3 Patented Aug. 1, 1944 CONTROLLER FOR, ELECTRIC MOTORS Walter E. Addicks, Wellesley Hills,Mass., assignor' to Cutler-Hammer, Inc., Milwaukee, Wis., a,

corporation of Delaware 7, Application December 7, 1'942,"Serial No. 468,067

6 Claims. (01. 172-179).

This invention relates to controllers for electric motors.

In the machine tool field the controlled machine frequently is provided with two or more motors, as for example a main driving motor and a motor for operating a coolant pump, and in some installations it is important to start the coolant motor when starting the driving motor, whereas at times the machine may be used for work rendering a, coolant unnecessary, and operation of the second motor wasteful of power. Also it may be necessary or desirable to locate the control box as well as the motors at the rear of the controlledmachine, whereas the operator may stand at the front of the machine, thus rendering highly desirable remote control through the medium of a small control station, and the present invention although not limited thereto relates particularly to control for such machines.

An object of the invention is to afford the aforeindicated desirable control of two motors through the medium of a remote control station which may be embodied in a very simple and compactform and which may be easily and conveniently operated.

Another object is to provide control of the aforementioned character enabling easy and quick adjustment which pending a further intentional adjustment will always afford starting of both motors or of only one of the motors, according to the adjustment last ;made.

Another object is to provide control of the aforementioned character which according to its adjustment will afford starting of both motors or of one motor only by operating a single push One embodiment of the invention is diagram matically illustrated in the accompanying drawing, and thesame will now be described, it being understood that the embodiment illustrated is susceptible of modification without departing from the scope of the appended claims.

Referring to the drawing, the same shows motors MI and M2 which may be assumed to be respectively the driving motor and the coolant motor for a machine tool. Themotors may, of course, be of any preferred type to be, supplied with power from a suitable source, as for example, lines LI,L2. I

The control means illustrated comprises an electroresponsive switch SI having contacts I push button switch I.

to connect motorMl across lines Lil, L2, andfan electroresponsive switch S2 having contacts 'Tt o connect motor M2 across lines LI,- LZ The switches SI and S2 are of the normally open type to be closed by energization of their windings 3 and 4, respectively. The switch S1 is shown as provided with -normally disengaged auxiliary contacts 5 for purposes hereinafter set forth; i

It will, of course, be understood, that the switches SI and S2 are merely representative'of any preferred form ofstarters forthe'm'otors 'MI and M2, and that'the starters whether of the simple character illustrated or of a more elaborate character would ordinarily be enclosed in a casing or box to be mounted in any preferred relation to the controlled machine. As aforeindicated it is quite customary in the case of 'machine tools to mount the control box as well as the motors at the rear of the machine.

Again referring to the drawing, the same shows for remote control of switches SI ands! a starting push button switch 6 and a stopping The push button switch I has but a, single set of contacts which are normally engaged as through the medium of a spring 8. The push button switch 6, on thev other hand, has two sets of stationary contacts 9 and I0 and a contact element II to bridge either the contacts 9 or the contacts Ill. The contact element II is biased asby a spring 12 toward thecontacts 9, whereas the push button of the contact element H has a lateral projection |3.'to be, engaged with a stop l4 to hold the contactelement ll out of engagement with contacts 9; 'As will be understood, the push button projection'or lug l3 and stop I4 are merely representative. of various well known means for limitingasdescribed the biased movement of a double acting push button switch, subject to releaseof said switch for full movement upon disengagement of the limiting means, as for example, by, rotary movement of the push button such asto disengage the lug l3 from the stop. Also as will be understood the lug l3 and stop M are representative of well known means which when set to limit movement of the push button remaineset until intentionally adjusted and which when set to permit full movement. of the push button remain so set pending further intentional adjustment. Thus with the adjustment illustrated it v will be observed that depression of the push button causes contact element H to bridge contacts "I, whereas release of the push button merely disengages contact element H from contacts inland switch 6 for automatic engagement of contacts II and 9 and that with both motors operating motor M2 may be stopped by adjusting push button switch 6 to disengage contact II from contacts 9. The motor M2 may be thus started and stopped without interfering with the operation of motor MI and ability of the controller to be so manipulated constitutes a very advantageous characteristic thereof, it being desirable as for setting up to have provisions for delay in starting of motor M2 pending a second manipulation cuit from line LI through contacts I and II by conductor I'I, through the contacts of stop switch 1, by conductor I8 through the operating winding 3 of switch SI to line L2. Release of push button switch 6 tends to deenergize switch SI, but meanwhile said switch has established for itself a maintaining circuit through its auxiliary contacts 5. This circuit extends from line LI by conductor I9 through contacts 5, by conductors 20 and I! to and through the stop switch to the winding 3 as previously traced. Thus the motor MI will start and continue to operate until stopped by failure of power or by depression of push button switch I to interrupt the maintaining circuit of the winding 3.

With the lug I3 of push button switch 6 adjusted for full movement of contact element II upon release of the push button, depression and release of the push button first effects energization of switch SI as aforedescribed and then effects energization of switch S2. More specifically with switch SI closed and with the contacts 9 bridged by contact element II circuit may be traced from line LI to and through the auxiliary contacts of switch SI to and through the stop push button switch I as previously described, by conductor 2I to and through the contacts 9 and II of the start switch, by conductor 22 to and through the winding 4 of switch S2 to line L2. Thus switch S2 is energized to start motor M2 and to cause it to continue to operate while motor MI operates, assuming the contact element I l to remain in engagement with contacts 9. Of course it will be understood that if desired the switch S2 might be provided with a maintaining circuit rendering its continued energization independent of the push button switch 6, and as will be understood both switches SI and S2 may be deenergized at any time to stop both motors by merely depressing the stop push button switch I.

It will be noted that the contacts 5 of the switch SI in addition to providing a maintaining circuit for said switch also control the circuit of the winding of switch S2 to prevent energization of the latter switch pending prior response of the former switch. Thus after stopping it prevents contact element II even though engaging contacts 9 from becoming effective to restart motor M2, until after operation of the push button switch 6 to again energize switch SI to start motor MI.

As will be obvious, the push button switches 6 and I may be embodied in a very simple and compact push button station which may be located as desired, and that as before pointed out operation of the station for operation of both motors or one motor only will be the same, assuming appropriate prior adjustment of the push button lug I3 relative to the stop I4.

It is also to be noted that after motor MI has been started with the push button switch 6 set to prevent operation of motor M2 the latter motor may be started at any time while the motor M I is operating merely by adjusting the push button of the controller, and it being desirable as for purposes of inspection to have provisions for stopping motor M2 while operation of motor Ml continues. Stopping of motor M2 may be effected merely by depressing and holding down push button 6 as long as desired and then releasing the push button for restarting of motor M2 or the push button may be depressed and adjusted for locking thereof to prevent restarting of motor M2 when the finger is removed from the push button.

What I claim as new and desire to secure by Letters Patent is:

l. The combination with at least two motors, of control means for said motors to effect operation of a given number or a lesser number thereof and comprising a control station having a control element biased in one direction and means to adjust the limit of biased movement of said control element, said control mean also comprising separate eleotroresponsive starting means for said motors controlled by said control element to start the aforementioned given number or lesser number of motors when said control element is operated and released, according to the adjustment of limit of biased movement of said control element.

2. The combination with at least two motors, of control means for said motors to efiect operation of a given number or a lesser number thereof and comprising a control station having a control element biased in one direction and means to adjust the limit of biased movement of said control element, said control means also comprising electroresponsive starters individual to said motors, one of said starters being rendered responsive to start its respective motor when said control element is moved against its bias to a given position and another of said starters being rendered responsive to start its respective motor when said control element is moved under its bias to another given position, the aforementioned limit adjusting means according to its setting enabling said control element to return to the last mentioned position or arresting said element to maintain the second mentioned starter inactive.

3. The combination with at least two motors, of control means for said motors to effect operation of a given number or a lesser number thereof and comprising a control station having a control element biased in one direction and means to adjust the limit of biased movement of said control element, said control means also comprising eleotroresponsive starters individual to said motors and interconnected to render response of one dependent upon prior response of another, the latter starter being rendered responsive by movement of said control element against its bias to a given position and the former starter being rendered responsive or inactive when said element is freed for biased movement according to the limit established therefor by said limit adjusting means.

4. The combination with at least two motors, of

control means for said motors comprising electroresponsive starters individual thereto and a push button control switch common to said starters, said push button control switch being biased in one direction and requiring movement in the reverse direction to efiect response of certain of said starters, while requiring movement in its biased direction to efiect response of another of said starters, response of the latter starter also requiring prior response of the former starter and biased movement of said push button switch to a given position.

5. The combination with at least two motors, of control means for said motors comprising electroresponsive starters individual thereto and a push button control switch common to said starters, said push button control switch being biased in one direction and requiring movement in the reverse direction to effect response of certain of said starters, while requiring movement in its biased direction to effect response of another of said starters, response of the latter starter also requiring prior response of the former starter and biased movement of said push button switch to a given position, said push button switch having means to vary the limit of its biased movement, thereby to render optional energization or inaction of said latter starter following response of said former starter according to the setting of said limit varying means.

6. The combination with at least two motors, of control means for said motors comprising electroresponsive starters individual thereto, a push button control station having a start push button and a stop push button each common to said starters and said start push button being biased to a given position but having limiting means which may be set to restrict its range of movement to exclude such given position, and circuit connections to render response of one of said 

